Electrical combiner box with improved functionality

ABSTRACT

A combiner box capable of monitoring energy output from a photovoltaic system (or other alternative energy system) having improved troubleshooting functionality, the ability to independently verify utility charges, and a mechanism for reducing incorrect readings of energy output and consumption due to noise and interference.

This application claims the priority of U.S. non-provisional patentapplication Ser. No. 13/769,121 filed Feb. 15, 2013, which claims thepriority of U.S. provisional patent application No. 61/633,716 filedFeb. 15, 2012.

TECHNICAL FIELD

The present invention relates generally to combiner boxes used inphotovoltaic systems and other alternative energy systems that areconnected to a utility grid. More specifically, the invention is acombiner box capable of monitoring energy output from a photovoltaicsystem (or other alternative energy system) having improvedtroubleshooting functionality, the ability to independently verifyutility charges, and a mechanism for reducing incorrect readings ofenergy output and consumption due to noise and interference from otherenergy monitoring devices on connected circuits (including otherphotovoltaic systems that are connected through the utility grid) andhousehold electronics.

BACKGROUND ART

Photovoltaic (PV) systems and other alternative energy systems arebecoming increasingly popular as the prices of oil and otherconventional energy sources continue to increase. However, alternativeenergy systems are expensive and have operational issues that presentseveral time-consuming problems for installers and consumers. Forexample, the use of energy monitoring devices to monitor the performanceand output of PV systems is well-known, however, these devices areusually positioned inside a home or building near an Internet connectionand far from the solar panels of a PV system. Therefore, these devicesoften give incorrect readings (false readings or false data) due toexternal noise from household electronics (including but not limited tofluorescent lights, LED lights, dimmers, electronic equipment, homeoffice equipment, and surge suppressors). Noise occurs when electricaldevices and circuits give off undesirable electrical signals whichdisturb or impair other useful or desirable signals.

False readings can also occur from interference (or cross talk). Crosstalk occurs when one energy monitoring device erroneously picks up data(monitoring signals) from another energy monitoring device on aconnected circuit.

Both noise and cross talk can cause energy monitoring devices to givefalse readings, which leads to increased service calls for installersand increased time spent troubleshooting this issue.

PV and other alternative energy systems that are used today also lacktroubleshooting functionality and the ability for consumers toindependently verify amounts charged by utilities for electricity.

Accordingly, it is an object of the present invention to provide adevice that reduces or eliminates noise, cross talk, and other types ofinterference with energy monitoring devices by household electronics andother energy monitoring devices.

It is another object of the present invention to provide such a devicethat has improved troubleshooting functionality.

It is further object of the present invention to provide such a devicethat allows consumers to independently verify amounts of electricityprovided by a utility company.

The following patents and patent applications may be considered relevantto the field of the invention:

U.S. patent application publication no. US 2012/0048328 A1 to Solon,incorporated herein by reference, discloses a system for monitoring andwireless transmitting solar array parameters such as current, voltageand temperature in real time while primarily housed within a recombinerbox.

U.S. patent application publication no. US 2010/0053867 A1 to Dunn etal., incorporated herein by reference, discloses a system and method formeasuring the performance of individual strings of PV modules in a PVarray, including a string combiner box with integrated capability formeasurement of string current versus voltage characteristic.

U.S. patent application publication no. US 2008/0147335 A1 to Adest etal., incorporated herein by reference, disclosing a monitoring systemand method for monitoring performance of individual power sources in adistributed power source system. A monitoring module is coupled to eachpower source to monitor and collect data. The collected data istransmitted over a power line to central analysis station for analysis.

US patent application publication US 2011/0141644 A1 to Hastings et al.,incorporated herein by reference, discloses a direct current arc faultcircuit interrupter for a direct current combiner box.

US patent application publication US 2006/0237058 A1 to McClintock etal., incorporated herein by reference, discloses a direct currentcombiner box with power monitoring, ground fault detection andcommunications interface.

US patent application publication US 2011/0036386 A1 to Browder,incorporated herein by reference, discloses a fully integrated andself-contained AC photovoltaic solar panel having a compressionconnector fitting for electrically connecting to the utility grid.

The reference manual entitled “Troubleshooting an Enphase MicroinverterSystem,” published by Enphase Energy, Inc., incorporated herein byreference, discloses the use of ferrite beads to isolate an Envoy energymonitoring system from interference.

DISCLOSURE OF THE INVENTION

The above and other objects are preferably achieved by a device,comprising: a housing; power distribution blocks mounted in the housingfor combining utility-compliant alternating current from a plurality ofinverters, carried over wires containing monitoring signals from theinverters at a first monitoring frequency, to provide combinedalternating current carrying the monitoring signals; wherein thecombined alternating current is connected in parallel with alternatingcurrent from a utility grid at a utility connection to trigger theinverters to produce the utility-compliant alternating current; whereinthe combined alternating current feeds power to the utility grid and alocal load connected to the utility connection;

noise filters tuned to block interference with the first monitoringfrequency, interposed between the power distribution blocks and theutility connection; and

a power outlet box having at least two outlets electrically connected toone of the power distribution blocks, wherein an alternative energymonitoring device can be plugged into one of the outlets and an internalEthernet bridge adapter that is connected to the Internet can be pluggedinto another of the outlets, wherein the alternative energy monitoringunit and the internal Ethernet bridge adapter can be connected for datatransfer, wherein the power distribution blocks provide the combinedalternating current to the alternative energy monitoring device whichextracts the monitoring signals as extracted monitoring signals, andwherein the internal Ethernet bridge adapter connected to thealternative energy monitoring device communicates the extractedmonitoring signals at a second monitoring frequency to a remote externalEthernet bridge adapter that is connected to a remote server;

whereby the noise filters reduce cross talk from other monitoringsignals from other inverters, and noise from devices using thealternating current from the utility grid.

Alternatively, the device, comprises a housing; power distributionblocks mounted in the housing for combining utility-compliantalternating current from a plurality of inverters, carried over wirescontaining monitoring signals from the inverters at a first monitoringfrequency, to provide combined alternating current carrying themonitoring signals; wherein the combined alternating current isconnected in parallel with alternating current from a utility grid at autility connection to trigger the inverters to produce theutility-compliant alternating current; wherein the combined alternatingcurrent feeds power to the utility grid and a local load connected tothe utility connection;

noise filters tuned to block interference with the first monitoringfrequency, interposed between the power distribution blocks and theutility connection; and

a power source electrically connected to one of the power distributionblocks and an alternative energy monitoring device operably connected tothe Internet, wherein one of the power distribution blocks provides thecombined alternating current to the alternative energy monitoring devicewhich extracts the monitoring signals as extracted monitoring signals,and wherein the alternative energy monitoring device communicates theextracted monitoring signals at a second monitoring frequency over theInternet to a remote server;

whereby the noise filters reduce cross talk from other monitoringsignals from other inverters, and noise from devices using thealternating current from the utility grid.

The device further comprises a home energy monitoring unit housed in thehousing and connected to the alternative energy monitoring unit for datatransfer, operably connected to the local load to provide data onconsumption by the local load of the combined alternating current andthe alternating current from the utility grid, whereby independentverification of utility charges is achieved.

The device also further comprises an alternating current surge protectoroperably connected to the power distribution blocks.

The device still further comprises circuit breakers mounted in thehousing to receive the utility-compliant alternating current containingthe monitoring signals from the plurality of inverters. Currentindicators operably connected to the circuit breakers indicate when theutility-compliant alternating current is delivered to the circuitbreakers from the plurality of inverters.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of a PV system that uses the present invention.

FIG. 2 is an elevational view from the front of the interior of a firstpresently preferred embodiment of the invention; and

FIG. 3 is an elevational view from the front of the interior of a secondpresently preferred embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, shown is a schematic of a PV system. One or moresolar panels (solar photovoltaic modules) 4 on the roof of a home orbuilding collect sunlight as direct current (DC). Inverters 5 (commonlycalled micro inverters) operably connected to the solar panels 4 convertthe DC into alternating current (AC). The inverters 5 are connectedtogether in “strings.” The AC they produce is the form of electricalpower that is used by homes and businesses.

The inverters 5 then transmit AC and monitoring signals (data on theperformance and output of the inverters 5, including but not limited tototal PV system energy production, inverter AC voltage, inverter ACcurrent, and panel DC voltage) at a first monitoring frequency overwires 6 from the inverters 5 to the present invention 7.

The transmission of signals over power lines (such as wires 6) iswell-known. Power line communication systems operate by transmittingmodulated carrier signals over the same wires that carry power.

The AC produced by the inverters 5 preferably complies with all electricpower requirements of the utility, such as voltage, waveform, andfrequency (utility-compliant) and contains monitoring signalstransmitted by the inverters 5.

The inverters 5 preferably generate and deliver AC only when they areconnected in parallel to AC supplied from a utility grid 10. If theinverters 5 do not sense AC from the utility grid 10, they turn off anddo not generate utility-compliant AC.

After the DC is converted to AC by the inverters, the AC and monitoringsignals travel along one or more wires 6 to the present invention 7,which combines the utility-compliant AC from each string of inverters 5to generate combined AC. The combined AC from the invention 7 thereafterfeeds power to a utility meter 9 and utility grid 10. It also feedspower to a home power distribution panel 8 (local load). The utilitymeter 9, utility grid 10, and local load 8 are connected at a utilityconnection (not shown).

Referring to FIG. 2, shown is a first presently preferred embodiment ofthe invention comprising a combiner box 7, which preferably is lockable,weather resistant, corrosion resistant, and has upper and lower vents15, 19 for ventilation through the box. The interior of the box hasenclosure mounting holes 23 and a mounting plate 21 for mountingelectrical components into the box. The box components, however, can beplaced in the box in any manner that allows them to be securely retainedtherein.

The box preferably has circuit breakers 18, which receive theutility-compliant AC from the plurality (strings) of inverters 5 throughthe wires 6. The circuit breakers 18 protect the PV system from overload(excess current), short circuits, and other electrical malfunctions,which can lead to excessive generation of heat, fires, and otherhazards. There is preferably one circuit breaker 18 for each string ofinverters 5 in the PV system. Each circuit breaker 18 also preferablyhas a current indicator 20 (such a LED light) operably connected to it.Each current indicator 20 preferably turns on to confirm its connectedcircuit breaker 18 and is receiving utility-compliant AC current fromthe connected string of inverters 5. The current indicators 20 assistinstallers in determining which string of inverters is malfunctioningwhen the PV system is not producing enough power.

Power distribution blocks 17 combine the utility-compliant AC (travelingfrom the circuit breakers 18, or directly from the inverters) intocombined AC. The combined AC then travels out of the box 7 to power theutility grid 10 and a home power distribution panel (local load) 8, asshown in FIG. 1.

Referring back to FIG. 2, noise filters 24 (such as ferrite toroids orferrite rings), which suppress high frequency noise in electricalcircuits, are preferably placed in the combiner box 7 between the powerdistribution blocks 17 and the utility connection (i.e. the local load 8and the utility grid 10). The noise filters are specially tuned to blockinterference at the first monitoring frequency that is used by theinverters 5 to communicate with an alternative energy monitoring device11 (such as the Enphase Envoy Monitoring System). The noise filters 24reduce cross talk from other monitoring signals given off by otherinverters in connected circuits, and reduce noise from other householddevices that are using the AC from the utility grid 10.

A power outlet box 13 (or any other power source) is preferablyelectrically connected to at least one of the power distribution blocks17 and the alternative energy monitoring device 11. The alternativeenergy monitoring device 11 is also operably connected to the Interneteither wirelessly or via an internal Ethernet bridge adapter 14 (such asNetgear Powerline wall-plugged AC Ethernet adapter Bridge). If anEthernet bridge adapter is used, it is connected to the power outlet box13 (or other power source) and to the alternative energy monitoringdevice 11 via Universal Serial Bus (USB), or other ports located on theEthernet bridge adapter 14, to accomplish data transfer. The presentinvention also preferably positions the alternative energy monitoringdevice 11 within the box 7, instead of within the home, to reduce theproblems of data loss over distance and false data due to noise fromhousehold electronics.

The power distribution blocks 17 provide AC (carrying the monitoringsignals at a first monitoring frequency) to the alternative energymonitoring device 11.

The alternative energy monitoring device 11 preferably extracts themonitoring signals (data) from the wires in the box 7 and sends theextracted monitoring signals over the Internet (either wirelessly orthrough the internal Ethernet bridge adapter 14) at a second monitoringfrequency to a remote server (not shown) (or a remote external Ethernetbridge adapter (not shown) that is also connected to the Internet and aremote server (not shown)) so that the monitoring signals (data) can beaccessed and viewed by consumer through a website, mobile app, or othersimilar means. Preferably, the second monitoring frequency is distinctlydifferent from the first monitoring frequency so that the noise filters24 in the box will not block any communication at the second monitoringfrequency.

The present invention also preferably includes a prominent externalindicator light 16, which quickly confirms if the combiner box isreceiving voltage from the utility grid so that the inverters 5 can turnon and deliver AC.

A surge protector device 12 operably connected to the combiner blocks ispreferably included in the combiner box 7 to suppress any severetransient electrical activity through the box.

An equipment ground wire bus bar 22, typically a strip, bar, or hollowtube made of copper, brass, or aluminum, is also preferably located inthe combiner box to help conduct electricity and prevent electric shockon non-current carrying metallic parts of the box. These are oftennecessary to meet electrical safety code requirements.

Referring to FIG. 3, shown is a second presently preferred embodiment ofthe invention, which is identical to first embodiment, but adds a homeenergy monitoring unit 25 (such as the Energy Detective TED 5000,PowerSave, Inc. Current Cost, or Energy Circle eMonitor). Preferably,the home energy monitoring unit 25 is connected to the alternativeenergy monitoring device 11 via USB or other ports, and monitors andrecords the energy consumption of a home or building. Alternately, thehome energy monitoring unit 25 can be connected directly to the internalEthernet bridge adapter via USB or other ports. The home energymonitoring unit 25 is preferably located within the box 7, instead ofwithin the home, to reduce the problem of noise from householdelectronics, and it is operably connected to the local load 8.

The data from the home energy monitoring unit 25 is preferably combinedwith the monitoring signals from the alternative energy monitoringdevice 11 and transmitted by the internal Ethernet bridge adapter 14over the Internet to a remote external Ethernet bridge adapter (notshown) connected to the Internet and a remote server (not shown) so thatthe data can be accessed and viewed by a consumer through a website,mobile app, or other similar means.

The home energy monitoring unit 25 allows consumers to independentlyverify utility charges by determining the differences between the amountof energy generated by the PV system (which is recorded by thealternative energy monitoring device 11) and the amount of energyconsumed by the home (which is recorded by the home energy monitoringunit 25).

Although the presently preferred embodiment is described in connectionwith a PV system (photovoltaic system), it can be used in connectionwith any system that combines multiple sources of AC electricity.

While the present invention has been disclosed in connection with thepresently preferred embodiments described herein, it should beunderstood that there may be other embodiments which fall within thespirit and scope of the invention as defined by the claims. Accordingly,no limitations are to be implied or inferred in this invention except asspecifically and as explicitly set forth in the claims.

INDUSTRIAL APPLICABILITY

This invention can be used whenever it is necessary or desirable tomonitor the output of a PV system (or other alternative energy system)while improving trouble shooting capabilities and reducing the timeconsuming problems associated with noise and cross talk.

1. A device, comprising: a housing; power distribution blocks mounted insaid housing for combining utility-compliant alternating current from aplurality of inverters, carried over wires containing monitoring signalsfrom said inverters at a first monitoring frequency, to provide combinedalternating current carrying said monitoring signals; wherein saidcombined alternating current is connected in parallel with alternatingcurrent from a utility grid at a utility connection to trigger saidinverters to produce said utility-compliant alternating current; whereinsaid combined alternating current feeds power to said utility grid and alocal load connected to said utility connection; noise filters tuned toblock interference with said first monitoring frequency, interposedbetween said power distribution blocks and said utility connection; anda power outlet box having at least two outlets electrically connected toone of said power distribution blocks, wherein an alternative energymonitoring device can be plugged into one of said outlets and aninternal Ethernet bridge adapter that is connected to the Internet canbe plugged into another of said outlets, wherein said alternative energymonitoring unit and said internal Ethernet bridge adapter can beconnected for data transfer, wherein said power distribution blocksprovide said combined alternating current to said alternative energymonitoring device which extracts said monitoring signals as extractedmonitoring signals, and wherein said internal Ethernet bridge adapterconnected to said alternative energy monitoring device communicates saidextracted monitoring signals at a second monitoring frequency to aremote external Ethernet bridge adapter connected to a remote server;whereby said noise filters reduce cross talk from other monitoringsignals from other inverters, and noise from devices using saidalternating current from said utility grid.
 2. A device, comprising: ahousing; power distribution blocks mounted in said housing for combiningutility-compliant alternating current from a plurality of inverters,carried over wires containing monitoring signals from said inverters ata first monitoring frequency, to provide combined alternating currentcarrying said monitoring signals; wherein said combined alternatingcurrent is connected in parallel with alternating current from a utilitygrid at a utility connection to trigger said inverters to produce saidutility-compliant alternating current; wherein said combined alternatingcurrent feeds power to said utility grid and a local load connected tosaid utility connection; noise filters tuned to block interference withsaid first monitoring frequency, interposed between said powerdistribution blocks and said utility connection; and a power sourceelectrically connected to one of said power distribution blocks and analternative energy monitoring device operably connected to the Internet,wherein said one of said power distribution blocks provides saidcombined alternating current to said alternative energy monitoringdevice which extracts said monitoring signals as extracted monitoringsignals, and wherein said alternative energy monitoring devicecommunicates said extracted monitoring signals at a second monitoringfrequency over the Internet to a remote server; whereby said noisefilters reduce cross talk from other monitoring signals from otherinverters, and noise from devices using said alternating current fromsaid utility grid.
 3. A device according to claim 1 or 2, furthercomprising a home energy monitoring unit housed in said housing andconnected to said alternative energy monitoring unit for data transfer,operably connected to said local load to provide data on consumption bysaid local load of said combined alternating current and saidalternating current from said utility grid, whereby independentverification of utility charges is achieved.
 4. A device according toclaim 1 or 2, further comprising an alternating current surge protectoroperably connected to said power distribution blocks.
 5. A deviceaccording to claim 1 or 2, further comprising circuit breakers mountedin said housing to receive said utility-compliant alternating currentcontaining said monitoring signals from said plurality of inverters. 6.A device according to claim 5, further comprising current indicatorsoperably connected to said circuit breakers to indicate when saidutility-compliant alternating current is delivered to said circuitbreakers from said plurality of inverters.